1. Field of the Invention
The present invention relates to a tape cassette, and particularly to a tape cassette which is desirable for a magnetic recording/reproducing device such as a video tape recorder or the like.
2. Description of the Prior Art
Generally, a conventional tape cassette to be inserted into a magnetic tape device such as a video tape recorder (which will be referred to as VTR hereinafter) or the like has a construction in which front and inner lids are provided on a front surface of a case and cover a magnetic tape which extends along the front surface of the case (for example, refer to Japanese Laid-Open Patent Publication No. 63-175279).
The above conventional tape cassette is described hereinafter with reference to the drawings.
FIG. 28 is a perspective view of the tape cassette of the prior art, and FIGS. 29 and 30 are sectional views of an important portion of the tape cassette of the prior art.
In FIGS. 28 to 30, an opening 61 is provided in a front surface of the tape cassette 64 along substantially the width of the cassette 64. A magnetic tape 59 is stretched over the opening 61 and is usually covered with front and inner lids 58 and 57.
The front lid 58 is free to rotate about a supporting point pin 65. A coil spring 66 is fitted to the supporting point pin 65 and always urges the front lid 58 to rotate toward a closing direction.
A pair of brackets 67 are provided at an upper and inner side of the front lid 58. A pair of supporting pins 60 provided at both left and right ends of the inner lid 57 are inserted into the brackets 67, and the inside lid 57 can freely rotate about the supporting pins 60.
A pair of guiding pins 55 provided at both ends of the inner lid 57 are inserted into a guiding grooves 56, and are free to slide therein. A locking member 50 is rotatably provided at the cassette case 68. A plate spring 70 is fitted to a rear side of the locking member 50 and urges the locking member 50 to rotate toward a forward direction.
Usually, a protrusion 52 provided on a side plate 54 of the front lid 58 is engaged with a click 53 of the locking member 50, such that the rotation of the front lid 58 can be prevented.
Operations of the tape cassette constructed as above are described hereinafter. The tape cassette 64 usually prevents the front lid 58 from carelessly opening by means of the locking member 50.
On the other hand, when the tape cassette 64 is inserted into the video tape recorder (which will be referred to as VTR hereinafter), the locking member 50 rotates in the D direction against the force of the plate spring 70 by means of a lock releasing member 71 provided at the VTR, such that the protrusion 52 becomes disengaged from the click 53 to enable the front lid 58 to rotate as shown in FIG. 30.
Then, when the tape cassette is moved in the E direction as shown in FIG. 30, the front lid 58 is opened upward. The supporting pins 60 on the inner lid 57 are moved upward about the supporting point pin 65 and the guiding pins 55 are guided along the guiding grooves 56. Thus the lids 58 and 57 are opened.
The above is the opening operations for inserting the tape cassette 64 into the VTR, and is reversed when the tape cassette 64 is being taken out.
However, in the above construction, a length from the tape surface extending along the front surface of the cassette to the front lid rotation supporting point is larger than that from the cassette bottom surface, so that a wider cassette opening is necessary and the cassette is relatively large considering the windable tape length.